<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>取消请求</title>
</head>
<body>
    <button>点击发送</button>
    <button>点击取消</button>
</body>
<script>
    // 
    //获取元素对象
    const btns = document.querySelectorAll('button');
    let x = null;
    btns[0].onclick = function(){
        x = new XMLHttpRequest();
        x.open("GET",'http://127.0.0.1:8000/delay');
        x.send(); 
    };

    //使用abort方法取消请求
    btns[1].onclick=function(){
        x.abort();
    }
</script>
</html>